The invention relates to a method and apparatus for producing galvanic primary cells, utilizing direct pressing of the depolarizer mass into a cup-shaped negative electrode.
During the production of galvanic primary cells according to the paperlining method, either a pressed element of depolarizer mass is brought into a lined zinc cup, or the depolarizer mass is pressed into the zinc cup after being proportioned in a mold (matrix).
For the manufacture of preformed elements, the depolarizer mass is conveyed via a controllable vibratory feed into a mold, in which it is slightly pre-compressed by a hammer device and then pushed into the mold (matrix) by a molding ram.
The quantity fed into the mold is overdosed by about twenty percent, so that the weight and density of the pressed element is within weight and density tolerances after having gone through the pressing and elongation operations. After removal from the mold (matrix), the pressed element, now called a dolly, is transported to the coiling machine by a so-called dolly-conveyor.
During the subsequent manufacturing process, the molded element is pressed again in the electrode cup.
To insert the molded element with its envelope into the cup without damage, its diameter must be slightly smaller than the inner diameter of the cup. Otherwise, paper tears within the coil can easily develop during subsequent pressing-in. Also the capacity is limited by the fact that the density of the depolarizer mass decreases toward the bottom of the cup.
In utilizing this method, relatively large variations in dosage can occur, as well as loss or backflow of the mass due to overdosing.
If the depolarizer mass is inserted into the lined zinc cups, considerable variations in dosage also occur due to uncompensated predosing. Again, the capacity is limited by the unequal density of the depolarizer.